allen



H. I. ALLEN.

PROCESS OF ELECTROLYSIS.

APPLICATION FILED FEB. 1. 19x7.

L303,226 Patented. May1'3, 1919 3 SHEETS-SHEET L- INMENTITZIfi HE EE TLALLE E y MATTE ,RNEYE H. l. ALLEN.

PROCESS OF ELECTROLYSIS.

APPLICATION FILED FEB.1.I91Z

L$U3,2260 Patented May 13, 1919. 3 SHEETS SHEET 2A Hg. 5

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IATION FILED FEB. I. 1917- Patented May13, 1919.

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+1 TED STATES PATENT OFFICE.

near I. ALLEN, or PORTLAND, MAINE, ASSIGNOR 'ro ELECTRON CHEMICAL COMPANY, or PORTLAND, MAINE, A CORPORATION or MAINE.

PROCESS OF ELECTROLYSIS.

" Specification of Letters Patent.

Application filed February 1, 1917. Serial No. 145,883.

To all whom it may concern:

Be it known that I, HERBERT I. ALLEN, a citizen of the United States, residing at Portland, in the county of Cumberland and State of Maine, have invented new and useful Improvements in Processes of Electrolysis, of which the following is a specification. I

This invention has relation to electrolytic cells and rocesses of electrolysis, and has for its Ob ect to provide certain improvements therein, in consequence of which they may be employed for the recovery of certain metals from the soluble salts thereof, such for example as the recovery of zinc from the chlorid or sulfate thereof, or the recovery of other metals which in their atomic state do not combine with water.

lln general, the electrolytic cell, embodying t e present invention, comprises a cathode upon which the metal cation may be deposited and which is immersed in the electrolyte, a diaphragm throu h which the electrolyte may percolate, an an anode in contact with the outer face of the diaphragm but unsubmerged in the electrolyte. With this construction, upon the passage of an electric current of suitable amperage from the anode to the cathode, the cationic cathode comp artment.

metal is deposited either as a film or as a sponge upon the cathode and the anions are liberated at the anode, so that they may be freed either as a gas or combine with the water of the percolated electrolyte according to the character of the salt being decomposed. Wherethe salt is in the form of a chlorid, chlorin is given off at the anode and may be recovered, whereas, where the electrolyte consists of a sulfate solution, the anion radical S9,, may combine with water to form, for example, sulfuric acid. Since the anode is unsubmerged, the efliuence of the excess percolated electrolyte from the anode side of the diaphra m prevents the return of the anionic su stances to the lhe cell is so constructed that the cathodes may be easily removed, when the layer of deposited metal is sufficiently thick, and then replacedby duplicates thereof.

The invention may be embodied in 'vari-. ous forms of cells, and I have illustrated and shall hereafter describe three 'forms which are practicable for recoveringzinc from zinc chlorid and zinc sulfate.

Referring to said drawings,-

Figure 1 represents in plan view an electrolytic cell havingan anode compartment and two exterior cathode compartments and especially adapted for chlorid solutions.

Fig. 2. represents a horizontal section through the same.

Fig. 3 represents a vertical section on the line 3-3 of Fig. 1.

Fig. 4 represents a section on the line 44 of Fig. 1.

Figs. 5 to 11 inclusive illustrate a form of cell useful for recovering zinc andother like metals from a sulfate solution,--Fig. 5 representing a plan view thereof, Fig. 6 a section on the line 6--6 of Fig. 5, Fig. 7 a

section on the line 7-7, and Fig. 8 a section on the line 8-8, Fig. 9 showing the diaphragm and gasket, Fig. 10 one of the laminae of the lead anode, and Fig. 11 the cathode.

Figs. 12 to 15 inclusive illustrate a third form of cell, Fig. 12 being a plan view, Fig. 13 an end View, Fig. 1 1 a side elevation, and Fig. 15 a section on the line 15-15 of Fi 14. p

n the various cells which I have illustrated, there are numerous eneric features, although they difier somew at in their details of construction. Each is provided with one or more cathode chambers or compartments in which is contained the electrolyte, and in each chamber there is a cathode for the deposit of the metal split by decomposition from the salt in solution. At least one wall of the cathode chamber consists of an inert material which is sufiiciently porous to permit a relatively "free percolation of the electrolyte through it; and in contact with the outer face of the wall is the anode, so that the percolated electrolyte will contact therewith and establish an electrical circuit from the anode to the cathode. The cathode has spaced ribs, engaging the diaphragm, and the cationic effluent passes between the ribs, or flows down through them, and is discharged, as a result of which there is no body or pool of electrolyte in which the anode is immersed. In each cell an inlet and outlet are provided so that the electrolyte may be circulated through the cathode chamber, to preventthe impoverishment of the salt in the electrolyte, and in each case, as previously indicated herein, the cathode or cathodes are easily'removable without 5 otherwise dismantling the cell.

Referring more particularly to Figs. 1 to 4 inclusive, the cell there shown is adapted more particularly for recovering zinc, for example, from an aqueous solution of zinc and chlorin. being liberated at. the anode. In this particular form of cell, the anode compartment is located between two cathode compartments, there being two diaphragms .trated, the cell is provided with the two side walls 20, 20, of any suitable inert mate-.

rial, such, for example, as wood. Each of the two end walls consists. of three sections 21, 22 and 23, divided in vertical planes, so that between the two outer and the intermediate sections may be placed'the diaphragms 24, 24, of asbestos cloth, asbestos consist of one or more layers as may be readily understood. The bottom of the cell also consists of three sections 25,26, 27. The space contained within the diaphragms 24, the sections 22 of the end wall and the The end walls project. above the side walls and they are connected by a narrow top consisting of the three sections 29, 30 and 31. By reason of this construction, it will the diaphragms are all firmly clamped between three separable sections of the cell body. These sections are firmly clamped together by bolts 32, 32, 33. The two spaces between the diaphragms and the outer side walls 20, 20, constitute the cathode chambers or compartments which it will be seen are open at their upper ends. The anode provided, however, with an eduction pipe 34 for the outflow of the gas liberated in said chamber. At the bottom of the chamber there is an eduction pipe 35 for permitting theoutflow of such electrolyte as percolates into the said chamber. The anode is indicated at 36 .and in this form of'cell it preferably consists of a block of Atcheson graphite which is substantially oblong in shape and which is provided on its opposite ,faces with alternating grooves and ribs, as

clearly indicated in Figs. 2 and 4. A car- .bon spindle 37, with a tapering lower end, is inserted in a-socket in the anode, said spindle projecting upwardly through. the

top ofthe anode chamber and being suitably equipped for the connection therewith 'of an electrical conductor. The anode is of such cross dimensions that it is in contact with the faces of both diaphragms 38, 38.

chlorid, zinc being deposited on the cathode with which the anode is in contact.- As illuspaper, or the like. Each diaphragm may section 26 of the bottom, constitutes the anode chamber which is indicated at 28.

chamber is closed at its upper end, being- The anode is also of .such height that its upper surface is substantially in the plane of the level of the body of electrolyte in the cathode chambers so as to leave a space thereabove for the gas. The two cathodes are indicated at 39, 39. Each consists of a metallic plate, preferably zinc or aluminum, and is thin enough so that it is more or less flexible. Each plate is inserted in the cathode chamber, the sections 21 and 23 of the end walls of the cell body being provided with grooves or ways 40.

It will thus be seen that the cathodes may be easily inserted in place and removed when desired, and that they are held in upright position with their faces confrontin the faces of the diaphragms. Any suitable means for connecting the electrical conductor to the cathode may be employed. The electrolyte is fed into the cathode chambers preferably to a point at the bottom of the chambers and between the cathodes and the diaphragms )by inlet pipes 41, 41, and the excess electrolyte is 'dlscharged from said chambers by pipes 42, the location of these latter'pipes definitely determining the height of the body of electrolyte in said cathode chambers. Each cathode plate is provided at its lower marginal portion with a notch 42 so as to fit over the pipe 41, as

best shown inLFig. 4.

The electrolyte, in this case an aqueous solution of zinc chlorid, is circulated through'the cathode chambers, being introduced into the lower portion of the space between the cathode and the diaphragm and flowing out through the pipe 42, from each of the cathode chambers.

In the operation of the cell, current of proper amperage being conducted to the anode, the current passes from the anode through such electrolyte as percolates through the diaphragm to the body of electrolyte in the cathode chamber, thence through the cathode and out. Upon the decomposltion of the zinc chlorid, zinc is deposited either as a film or as a sponge upon the cathode simultaneously with the liberatlon of chlorin on the anode. The chlorin may be withdrawn by a vacuum pump or chambers in this cell, there are but two, one I 'ano'decompartment and one cathode compartment. The cell body does not differ essentiallyfrom that previously described, except that it is formed in two separable sections and is not provided with a top. In

this case, the diaphragm is indicated at 50 and is clamped between the two sections of the cell body. The upper marginal edge of the diaphragm is held against the cathode by a gasket 51. The cathode 52 is removably fitted in grooves formed in the walls of the cathode chamber and fronts the face of the diaphragm. The anode 53 in the present case consists of lead strips or laminae, one of which is shown at 51. 'At their upper ends these laminae are held apart by spacers 55 and a lead bar 56 is passed through the strips and spacers so as to connect them all together, and also to serve for the transmission of electrical current thereto. The said bar projects through the end wall of the said body and is illustrated in Fig. 5 as having an electrical conductor connected therewith. The strips and spacers, which constitute the anode, bear against. the anode side of the diaphragm, the edges of the strips making cont-act with such electrolyte as percolates the-rethrough. The strips and their intervening spaces constitute, as it were, ribs and grooves, more or less of the electrolyte being held in the spaces or grooves by capillary action. Upon decomposition of the zinc sulfate, zinc is deposited upon the cathode; and the acid radical which is liberated at the anode combines with water to form sulfuric acid with the liberation of oxygen. There is no accumulation of liquid in the anode chamber as it is withdrawn through the eduction pipe 156 leading therefrom, as illustrated in Figs. 5 and 6.

I11 Figs. 12 to 15 inclusive, I have illustrated a very simple form of electrolytic cell for recovering zinc from an aqueous solution of zinc sulfate. The cell body rests upon a stand of any suitable type. I have illustrated a stand consisting of uprights 60, 60, and a longitudinal member 61. This stand may be cast of concrete if desired. Upon it rests the cell body which consists of a frame having a bottom 62 and upright ends 63. Against the side faces of the frame are the two diaphragms 61 and the two anodes 65, (55, which are secured in place by clamp bars (36. 67. Bolts 68 clamp-all of these parts firmly together. The cathode 69, which is removable, is held in grooves in the cell body and located midway between the diaphragms. The cathode projects above the cell body and may have a conductor secured thereto as shown in Fig. 13. The anodes preferably consist of lead plates, each having a series of narrow slots so as to constitute alternating grooves and ribs. The elcc' trolyte is fed into the cathode chamber through the pipe 691 and is conducted away from each by a pipe 70. Immediately below the anodes, the supporting member 61 is provided with grooves 71 to receive the etlluent from the anodes and to conduct it to the end of the supporting frame, where it is discharged into a suitalble receptacle.

The three cells, which I have herein illustrated are all very simple and cheap in construction, may be easily disassembled to replace the worn diaphragm, and are highly efiicient. There are no dangerous gases liberated in the anode chambers or compart ments when the sulfate is being elec-trolyzed and the anodes may therefore be open to the atmosphere. Of course, where chlorin is liberated at the anode, provision must be made for preventing its discharge into the cell room. No dangerous gases are in any case evolved in the cathode chamber.

Having thus explained my invention and several cells in or by which the invention may be embodied and practised, what I claim is 1. A process of recovering from an aque ous saline solution a metal which in its atomic state does not combine with water, which consists in causing a body of said solution contained in a cathode chamber to percolate through a diaphragm, passing an electric current from an unsubmerged node in contact with said diaphragm and percolate-d solution through said solution to a cathode immersed in the solution on the other side of the diaphragm, thereby decomposing the salt contained in the solution, depositing the cationic metal on the cathode, and liberating the anions at the anode, either to be freed as such or to combine with the water of the solution according to the char acter of the original salt.

2. A process of recovering zinc or equivalent metal from the sulfate thereof, which consists in causing a body of an aqueous solution of such sulfate, as an electrolyte, to percolate from a cathode chamber through a diaphragm into contact with an unsubmerged anode contiguous to said diaphragm, and passing an electric current from said anode through said solution to a cathode submerged in the electrolyte on the other side of the diaphragm, thereby decomposing said sulfate, depositing the free metal on said cathode, and liberating at the anode a molecular anion which combines with the percolated water to form sulfuric acid..

In testimony whereof I have affixed my signature.

HERBERT I. ALLEN. 

